Provided a gas diffusion layer for fuel cells, the gas diffusion layer including: a carbon substrate; and a microporous layer formed on the carbon substrate, wherein the microporous layer comprises first carbon particles having a partially graphitized structure and a water-repellent binder resin binding the first carbon particles, and the microporous layer further comprises a cerium compound, a nitrogen-doped cerium compound, nitrogen-doped second carbon particles having a partially graphitized or non-graphitized structure, or a mixture of two or more, as a radical scavenger capable of removing hydrogen peroxide generated at a fuel cell open circuit potential or a higher potential. In the membrane electrode assembly and the fuel cell each employing the gas diffusion layer having excellent durability according to one or more embodiments, chemical or electrochemical degradation may be effectively prevented over a long period of time, and thus excellent electrochemical performance may be obtained over a long period of time. This leads to an extended lifetime of the fuel cell.

a fuel battery includes a membrane-electrode assembly (MEA) in which a catalyst layer and a gas diffusion layer are stacked on each of opposite surfaces of a polymer electrolyte membrane; and separators between which the membrane-electrode assembly is interposed, wherein each of the separators includes a rib and a groove on a surface that is in contact with the gas diffusion layer, the rib and the groove forming a gas flow path through which a reaction gas to be used for power generation flows, when a thickness of the gas diffusion layer is defined as h, and a width of a portion of the rib that is in contact with the gas diffusion layer is defined as Rw, 0.29 Rw≤h≤0.55 Rw is satisfied, the gas diffusion layer includes conductive particles, conductive fibers, and a polymer resin, and average fiber length Fl and average fiber diameter Fd of the conductive fibers satisfy Fl<Rw/2 and Fd<h/100.

A gas diffusion layer includes: a conductive particle; and a fluororesin, and the fluororesin includes a first fiber having a first average fiber diameter and a second fiber having a second average fiber diameter different from the first average fiber diameter.

A manufacturing method for manufacturing a fuel cell includes a laser application step and a bonding step. In the laser application step, a laser beam is applied to a carbon film of a separator including a metal plate and the carbon film covering a surface of the metal plate such that the metal plate is exposed by removing the carbon film within an application range of the laser beam. In the bonding step, the separator is bonded to a resin member within a range including at least part of a range where the metal plate is exposed.

A manufacturing method for manufacturing a fuel cell includes a laser application step and a bonding step. In the laser application step, a laser beam is applied to a carbon film of a separator including a metal plate and the carbon film covering a surface of the metal plate such that the metal plate is exposed by removing the carbon film within an application range of the laser beam. In the bonding step, the separator is bonded to a resin member within a range including at least part of a range where the metal plate is exposed.

A fuel cell includes an electrolyte membrane-electrode assembly, a durability enhancing layer formed on at least one side of the electrolyte membrane-electrode assembly, and a gas diffusion layer formed on a side of the durability enhancing layer opposite a side on which the electrolyte membrane-electrode assembly is formed, wherein the durability enhancing layer includes a hydrogen peroxide decomposition catalyst and a hydrogen ion conductive polymer and is formed on at least a part of the at least one side of the electrolyte membrane-electrode assembly.

Provided is a gas diffusion layer, in which a microporous layer has an inner wall of through passages and a region adjacent to the through passages containing a greater amount of a water-repellent binder resin than a region not adjacent to the through passages, and thus water formed by an electrochemical reaction is effectively discharged from the gas diffusion layer. When the gas diffusion layer of the present invention is used, an optimal water management may be possible for smooth operation under all humidity conditions including a high humidity condition and a low humidity condition, and thus a fuel cell having improved cell performance may be obtained.

An apparatus for manufacturing a gas diffusion layer for fuel cells includes: a conveyer transferring a base sheet for a macroporous layer of the gas diffusion layer in one direction before water repellent coating; a nozzle disposed around the conveyer to coat the transferring base sheet with a water repellent in a fiber type or desired pattern; and a nozzle transfer unit combined with an upper end of the nozzle to transfer the nozzle along a desired trajectory.

An apparatus for manufacturing a gas diffusion layer for fuel cells includes: a conveyer transferring a base sheet for a macroporous layer of the gas diffusion layer in one direction before water repellent coating; a nozzle disposed around the conveyer to coat the transferring base sheet with a water repellent in a fiber type or desired pattern; and a nozzle transfer unit combined with an upper end of the nozzle to transfer the nozzle along a desired trajectory.

An electrode for a redox flow battery through which an electrolyte is circulated includes a porous body, and reactive particles that contribute to a battery reaction. The reactive particles are pressed against the porous body by a flow of the electrolyte without being immobilized on the porous body.